IR flares are used as military decoys for infrared heat seeking missiles, for defensive or practice purposes. The flares that are now in use are made from a pyrotechnic magnesium-teflon composition. However, this composition is not entirely satisfactory for defeating more refined missle seeker-heads since the magnesium-teflon flare is a point source and radiates like a grey body, characteristics that do not adequately simulate the IR emissions from an aircraft. These deficiencies could be ameliorated if a pyrophoric fuel could be used instead of the traditional pyrotechnic materials.
The main advantages of pyrophoric fuels for flares are:
(a) Some pyrophoric fuels burn in much the same way as hydrocarbons, thus the infrared emission from pyrophoric flames is similar to that of kerosene. Thus, pyrophoric flares would give an infrared spectral signature much closer to the one given by an aircraft. PA1 (b) Pyrophoric flames are extended sources and so the IR image of a pyrophoric flare would more closely resemble that of an aircraft. PA1 (c) Pyrophoric fuels can use ambient air as an oxidizer. This allows a large proportion of the flare volume to be used for fuel. PA1 (d) In principle, they ignite spontaneously in air, PA1 (a) a supply of fuel; PA1 a fuel ejector for ejecting a stream of the fuel into an ignition space; PA1 (c) a supply of oxygen; PA1 (d) oxygen injector means for injecting a flow of oxygen into the stream of fuel in the ignition space; and PA1 (e) a shroud sheltering the ignition space.
Despite these advantages, pyrophoric flames have, until now tended to blow out under extreme wind and high altitude conditions. To the best of the applicant's knowledge, there is no pyrophoric fuel dispensing system now available that can, under these extreme conditions, successfully eject the fuel into the surrounding atmosphere to allow combustion with ambient air while anchoring the flame to the fuel dispensing system.